Intaglio printing and embossing press



Dec. 30, 1952 H. B. GABBERT 2,623,457

INTAGLIO PRINTING AND EMBOSSING PRESS Filed Aug. 12, 194'? 5 Sheets-Sheet l I l3 l7 fi) I, ml

. INVENTOR. HOLM ES B. GABBERT ATTOR N EY Dec. 30, 1952 H. B. GABBERT 2,623,457

INTAGLIO PRINTING AND EMBQSSING PRESS Filed Aug. 12, 1947 5 Sheets-Sheet 2 IINVENTOR. HOLMES B GABBERT AT TOR N EY Dec. 30, 1952 H. B. GABBERT INTAGLIO PRINTING AND EMBOSSING PRESS Filed Aug. 12, 1947 5 Sheets-Sheet 3 INVENTOR.

HOLMES. B GABBERT ATTORNEY TOR ABBERT VEN ATTORNEY w W n 5 Sheets-Sheet 4 HOLMES B H. B. GABBERT INTAGLIO PRINTING AND EMBOSSING PRESS Dec. 30, 1952 Flled Aug 12 1947 Patented Dec. 30, 1952 UNITED STATES PATENT OFFICE INTAG L10 PRINTIN G AND Ell 50$ SING PRES S 7 Claims.

This invention relates to a printing and embossing machine, and, in particular, to a press for the running of intaglio plates and dies in embossing and printing.

More specifically, this invention relates to presses on which intaglio printing and embossing done by means including a plunger or similar element moving up and down to produce the required pressure of the paper against a die or plate.

One or" the problems associated with such printing machines is the dimculty of providing satisfactory, adjustable, and controllable means for producing the proper amount of pressure of the paper against the plate or die with each impression. Due to the fact that heavy pressure is required, especially with fine engraving and embossing, and to the fact that intaglio printing and embossing is done on paper of various textures, weights or thicknesses, it is necessary not only to be able to make fine adjustments in the positioning of the plunger, or other element by which the paper and the die or plate are pressed into impression-making contact, but also to guard against increasing the pressure, as a result of such adjustments, to the point where damage or danger occurs. It is not unusual for the heads or plunger supports in intaglio presses to become cracked and otherwise permanently damaged as a result of insufiicient care in making such adjustments and permitting a pressure to be developed which even the customary massive frames of such presses cannot stand. Other difiiculties also arise with excessive pressure even if the press is not actually damaged.

An object of the present invention is to provide a press having novel and improved means whereby fine adjustments in the positioning of the plunger element can easily be made.

A related object is to provide associated means for preventing destructive pressure, or any pressure in excess of a predetermined maximum, being set up in spite of carelessness in making adjustments.

Another object of this invention is to provide an improved press which can quickly be set ,to

produce the exact pressure desired for intaglio' printing or embossing with a particular die or make-ready press.

A further object of this invention is to provide an improved press of the character described in which the plunger or moving pressureproducing elements, by which the paper and die or plate are momentarily pressed against each other, will be located below thedle instead of above it, enabling the tracks on which the carriage for the die or plate is mounted to be spaced on each side of the die carriage anvil. There are several advantages in such arrangement. It

enables the upper portion of the press to be considerably reduced in size, and makes the entire machine more compact and of smaller overall dimensions. It also enables the sheet, which is to be printed or embossed, to be fed to the machine right side up and this fact, and the fact that it is not necessary to confine the paper feeding means to the usual small space left above the die or plate, facilitate the attachment and use of an automatic feeder.

An additional object of this invention is to provide an improved simple and practical construction for certain parts of the press as hereinafter described.

The manner in which these objects and advantages are attained will be apparent from the following description in which references are made to the accompanying drawings.

In the drawings:

Fig. 1 is an exterior view, in perspective, of my entire press, the external power drive means and power connections being omitted therefrom;

Fig. 2 is a corresponding front elevation drawn to slightly larger scale, of the pressflw'ith the lower front plates of the housing removed to show part of the mechanism located therein;

Fig. 3 is a front elevation, drawn to a larger scale, of the same mechanism located in the housing including the plunger and the supporting and operating means associatedwith the plunger, with portions broken away to show the construction and arrangement of certain parts;

Fig. 4 is a corresponding side elevation of the mechanism taken within the housing, with portions broken away;

Fig. 5 is a fragmentary staggered vertical sectien on line 5-5 of Fig. 3;

Fig. 6 is a dissected front elevation of part of the mechanism of Fig. 3, the members being shown separated from each other for the sake of clarity but arranged more or less in their related order, this figure being drawn to the same scale as Fig. 3 and with portions shown in section for further clarity;

Fig. 7 is a side fragmentary elevation corresponding to line l--T of Fig. 3 but with the connecting cap joining the upper and lower toggle elements removed;

Fig. 8 is a side elevation offthe; emergency access? 3 toggle-throw-out bevel assembly drawn toa smaller scale than Fig. 3;

Fig. 9 is a corresponding front elevation of the same lever assembly;

Fig. 10 is a front elevation, drawn on an enlarged scale, of the positioning gage for the hydraulic piston control which serves to indicate the relative maximum raised position of the plunger of my press;

Fig. ll is a fragmentary section on line ll-"-|I of Fig. 10;

Fig. 12 is an enlarged vertical section taken approximately through the center of the hydraulic cylinder and associated elements comprising the lower part of the mechanism of Figs. 3 and 4;

Fig. 13 is a staggered section corresponding to line I3--I3 of Fig. 12; and

Fig. 14 is a fragmentary vertical section on line. Iii-l4 of Fig. 13.

My improved press is, for the most part, contained within a housing indicated in general by the reference character I! in Fig. 1. Below the top or head portion of the housing H the front of the housing is recessed and open to constitute the throat ,I-2 in which the actual printing or embossing takes place. A feed table platform [3 is located in the bottom of this recessed portion of throat I2 and is attached to the plunger head (to be described later). The feed table platform carries the companionpressing. plate or the male portion of the intaglio plate assembly. The paper, or other material, which is being printed or embossed, is placed in position on platform l3 and then pressed against the die or plate mounted in the carriage above theplatform 13.

The die or plate, indicated at M in- Figs. 1 and 2, is slidably mounted on a pair of horizontal tracks l and mechanism (not shown) is provided for moving the die or plate, after the customary inking and wiping, to the forward position above the plunger head in synchronism with the movement of the plunger head so that the die or plate will bein its forward horizontal position when the plunger head. presses the sheet of paper deposited on the feed table platform up against the die or plate. Then with the withdrawal of the plunger head downward the die or plate is moved back into' the housing. where it is again given the customary inking and wiping preparatory to being returned to the forward position for the printing of the next sheet, provided ink is being used, or, in special embossing, the die may be caused to remain in front position. lflfhile various mechanisms and devices for inking and wiping the die or plate and for moving. it into operative and inoperative positions such as those now in common use. on presses for intaglio printing or embossing may be employed in this machine, I' have provided an improved special mechanism for this purpose which, however, will be thev subject of a subsequent application for patent and with which this present application is not concerned.

The plunger assembly (Figs. 3 and 4) includes a main plunger member l6 carrying a head plate I? and supported by upper and lower toggle membersIB and I9. The lower toggle member I9 is hingedly supported on a base block 20 whichrin turn is mounted on the top of a hydraulic positioning piston 2|. The base block 20 ordinarily remains stationary but its position may be adjusted, that is it may be raised or lowered, by raising or lowering the supporting hydraulic piston 2|, as will beexplained-later.

The main plunger member 16 is slldable up and down between suitable bearing blocks 22 (Figs. 3 and. 4). This main plunger member comprises a heavy solid metal block preferably formed with a central chamber 23 extending inwardly from the rear wall and sealed by a rear plate 24 (Fig. 4) Oil packing is placed in the chamber 23 and the chamber is kept filled with oil which is supplied through anoiling inlet 25. Small outlet holes 26 are drilled through the bottom of the plunger member I6 into the chamber 23 to provide lubrication for the bottom of the plunger member l6, and similar small lubrication holes 21 are drilled through the rear plate 24 and through the sides of plunger member Hi, to provide proper lubrication for the surfaces of the plunger member 16.

The bottom of the plunger member I6 is formed with a concave groove 28, the curvature of which corresponds to the semicylindrical top surface of the upper toggle member l8 (Figs. 4 and 5) and this groove constitutes a bearing for thetop of the upper toggle member l8. The bottom of the upper toggle member [8 is formed with a central curved groove 29 (Figs. 3, 6 and 7), and the top of the lower toggle member I!) has an identical curved groove 30 similarly centrally located. and

similarly extendin from one side of the toggle member to the other. The curvature of these grooves 29 and 30 corresponds to the radius of a shaft 3| which shaft rests in the groove 30 of the lower toggle member 19 and on which shaft the upper member H3 in turn rests. The bottom of the upper toggle member 18 slopes upwardly from each side.- of the groove 29, as shown in [8' in Fig. 7 and the top of the lower tog le member [9 on each side of the groove 30 similarly slopes downwardly as shown at l9 to permit the usual.

toggle joint movement of the members l8 and I9 without interfering with each other.

The two toggle members l8 and I9 and their mutual bearing shaft 3| are kept in operative relationship by a pair of cup-shaped caps 32 and 33 (Figs. 3 and. 6) which are attached to the respective. ends of the shaft 3| by screws 34 extending through the caps. into threaded holes in the ends of the shaft 3|. The sides of the toggle members I8 and 19 are formed with circular grooves 35 (see also Fig. 7) to accommodate the flanged rims of the cup-shaped caps 32 and 33.

A portion of the bottom of upper toggle mem berl8 and a similar portion of the top of lower toggle member l9 are cut away to provide space forfree movement of a roller 36 which is rotatably mounted on the shaft 3!. The roller 36 is adapted to" have rolling contact with a rotating cam 3'! (Fig. 4) secured to a shaft 38. The shaft 38 and with it the cam 31 are rotated by external power driving means (not shown). Tension springs 39' having their upper and lower ends secured to pins 39', mounted in the. sides of the upper and lower toggle members I8 and I9 respecti'vely, tend to cause the toggle members to thrust the roller 36 back and thus keep the roller 36 pressed against the perimeter of the cam 31 at all times so that roller 36 acts as the cam follower'.

.Thus it will be. apparent from Fig. 4 that-,ras the cam 37 is rotated, the two toggle members l8 and 19 will move alternately away from and towards alignmentwith each other, the members 18 and 19 never coming into entire alinement with each other, but, when reaching their maximum extended or full line position shown in Fig. 4, coming, within. a few degrees of. complete alinement. With the base block remaining stationary this movement of the toggle members towards and away from alinement produces up and down movement of the main plunger member l5 with its head plate H.

The head plate i! (Fig. 3) is slidable into place on the main plunger member it between a pair of guide bars 14 which are secured to the sides of the member l6 at the top, and the side edges of the head plate ll are formed into a sliding fit with the corresponding grooves in the guide bars 14.

The rear wall of the groove 28 on the bottom of the plunger member 16 is of less depth than the front wall and the rear side of member l6 slopes obliquely, indicated at H in Fig. 5. This is to enable the top of the upper toggle member it to be pushed rearwardly out of engagement with the groove 28, in case of emergency, and subsequently to be pulled back into such engagement.

The circumstances under which such emergency might arise making it desirable temporarily to disengage toggle member l8 and plunger mem-- her it will be explained later.

A bell-crank lever 88 (Figs. 3, 8 and 9), pivotally mounted at 8| on the inside of a side wall of the housing i l, carries a roller 82 at its upper end which bears against the front face of upper toggle member is near the top of the toggle member. A link 33 connects the opposite end of the bell-crank 39 with a foot pedal arm 84. The arm 34 is pivotally supported on the housing I! at 85, is movable up or down in a guideway '55, and the forward end extends out in front of the housing H and carries an adjustable foot pedal 81.

From Figs. 3, l, 8 and 9 it will be apparent that. if the foot pedal 87 is pressed down, the upper end of toggle member !8 will be pushed out of the groove 28 in the bottom of plunger member l5 and thus the toggle member will be temporarily disengaged from the plunger member it. However, when pressure on the foot pedal 3 is released, the springs (Figs. 3 and 4) will act to pull the upper end of toggle i3 bacl: into the groove 28. gle end out of groove 28 and the subsequent pulling of it back into groove 2% the rear wall of groove 28 is partly cut away, as previously mentioned, and has a rounded edge (Figs. 4 and 8).

When the toggle member 18 is disengaged from the plunger it the latter is prevented from dropping down too far by the engagement of the guide bars 74 (Fig. 3) with the bearing blocks 22.

If, while the press is operating, it should happen that no sheet of paper is in position for being pressed against the die or plate, the operator, by pressing his foot on the foot pedal Bl, can quickly prevent the plunger and plunger head from being pushed upwardly even though the running of the press is not stopped, and thus prevent the head plate I! from being pushed into direct contact with the die or plate.

The bottom end of the lower toggle member 19 has a hinge connection with the base block 22) Figs. 3, 4 and 5). To provide for this hinge connection the bottom end of toggle member [9 is formed with a central extension [9a (Figs. 3 and 6) while the base block 2!) is formed with a central recess Zea. A hinge shaft 15 extends through side portions of the base block on both sides of the central recess 20a and through thetoggle member extension Illa. The opposed surfaces at the top of base block 2!! and at the bottom of. toggle member 19 are curved as shown at 40 and 4| respectively (Fig. 4) to permit freedom To facilitate the pushing of the togof hinged movement of the toggle member I 9 with respect to base block 20. The bottom face of base block 20 has a circular recess 42 (Figs. 5 and 12) into which the top of the hydraulic piston 2| is fitted.

The hydraulic piston '2! (see Fig. 12) is mounted for vertical movement in a hydraulic cylinder. While the hydraulic cylinder may be formed in various ways, in my preferred form of construction, as illustrated in Figs. 12, 13 and 14, the cylinder comprises a base 43 having an integral upstanding circular flange 44. The flange 44 is threaded on its inside face and these threads engage with the threads at the lower portion of the outside face of the cylindrical wall 45 which constitutes the inner wall of the hydraulic cylinder. A cylinder head 46 has a similar downwardlyextending circular flange 4! which is threaded on the inside face and the threads of which engage 7 threads on the upper portion of the outside face of the cylindrical wall 45. An outer wall 48 extends over the outside faces of the flanges 4! and 44 and thus forms an. annular closed chamber 49. The cylinder head 45 is threaded on its outer periphery and a piston-adjusting cap 50 with a' downwardly-extending peripheral flange has corresponding engaging threads on the inner face of the flange so that the cap is secured in place on the cylinder head it and may be raised or lowered with respect to the cylinder head by turning the cap on the cylinder head.

The piston 2! (Fig. 12) has an annular shoulder 5! with a reduced diameter portion extending above the shoulder. The piston-adjusting cap ilil has a central circular opening the diameter of which corresponds to the diameter of the reduced portion of the hydraulic piston 2|. Thus the cap 50 limits the upward movement of the piston 2!. The outer face of the flange of the cap 59 is provided with gear teeth 52 (see also Fig. 4) which are adapted to be engaged by a worm gear 53 mounted in a support 54. The worm gear shaft extends through the lower front plate of the housing H and a hand wheel 55 is secured to the outer end of the worm gear shaft.

mitted by the cap 59 as shown in Fig. 12. The

piston is provided near the bottom with suitable packing or sealing rings indicated at 58 to form sliding sealing contact with the inside cylinder Wall :35 of the hydraulic cylinder.

Hydraulic fluid is initially supplied through the inlet channel 55 the outer end of which is connected to any suitable source of hydraulic fluid (not shown). The inner end of channel 5:? discharges through a ball valve 69 into the bottom of the hydraulic cylinder. A branch passageway i2 connects the channel 59 with. the an nular chamber t9. (Fig. 12). Enough hydraulic fluid is initially supplied to fill the space in the hydraulic cylinder below the piston 2! and also to'fill the annular chamber 19 part way. Then the outer end of channel 59 is closed with a threaded plug 19.

A safety relief valve 62 is located in the channel El extending from the bottom of the hydraulic cylinder, and this safety relief valve is 7 normally heldv closed by the spring ESVThe' spring. as is lccated ina cavity {ii the outer end of which is closed by a screw plug: 65 and the screw plug.

65 also serves to adjust the tension of the spring 64 and thus to determine the pressure within. the hydraulic cylinder required to open. the safety relief. valve 62. A passageway 66: connects the cavity fitwith the annular chamber 49 extending around the hydraulic cylinder.

A: pressure gage outlet 61 (Fig. 13:) is also. lo-

cated in the bottom of the: hydraulic cylinder and. connects with a gage pipe 68 which. extends. to some convenient location on the: press housing: where the pressure gage 69' is mounted.

' The interior of the hydrauliccylinder and the annular chamber 49 about the cylinder are also connected by a. passageway 10 controlled by: a The.

manually operableneedlevalve I I (Fig. 14') needle. valve H is normally kept closed, but'may be opened to permit hydraulic fluid to escapefrom the hydraulic cylinder when it is desired to lower the pressure.withi'nthe same or to lower the cap 501 A further passageway 12 connects the annular chamber! with the inlet channel 59 (Fig; 12). Thus hydraulic fluid may be drawn from the annular chamber or reservoir 49 through the passageway 12 and. channel 59 into the: hydraulic chamber but hydraulic fluid cannot pass from the: hydraulic chamber unless the needle valve H is opened or unless suflicient'pressure is developed with. the hydraulic chamber to open the. safety relief valve 62'. Instead of the annular chamber 49 another" suitable reservoir could of course be similarly connected with the hydraulic cylinder.

Anair exhaust channel 13 is located in: the top of the hydraulic piston 21. This channel 13 is normally kept closed by a screw plug but may be opened occasionally to exhaust any air which might collect in time within the hydraulic cylinder;

Since areserve of hydraulic fluid is maintained in the annular chamber 49' the action of the spring 51 causes the hydraulic plston H to be pushed upward to the extent permitted by the pistonadjustingv cap 50 and will cause hydraulic fluid to be drawn into the hydraulic cylinder through the passageway 72 and channel 59 to keep the cylinder filled with hydraulic fiuid and thus hold the piston. in position. downward pressure on the piston will be resisted not only by the spring 51 but also, as long as the. needle valve ll remains closed, by the noncompressible hydraulic fluid in. the cylinder. However, should such. downward pressure on the piston. become too great, the pressure relief valve 62' will be forced open allowing some of' the hydraulic fluid to pass back into the annular chamber 49.

Preparatory to the operation of my press the approximate maximum height to which it is desired to have the plunger" head rise in pressing the paper against the die or plate is deter mined. can be done by having the die or plate in the forward printing position previously mentioned, by having the cam 31 and toggle members It and I91 in the full line position shown in Fig. 4 and thenv turning the hand wheel 55' until the top of the plunger head is properly ad'- justed with respect to the die or'pl'ate. M'y press is then ready for operation- If it is-found from the first one or two sheets which are printed that the paper is not being held against the die with sufficient pressure this condition is quickly remedied by turning the hand wheel. 55* so as to Subsequent 8v raise the cap 59 and therewith permit the--pis'-'-- ton 2| to be: adjusted upwardly. This is' done when the plunger is in lowered position. On the other hand, if the piston has been raised too high, thus causing excessive pressure to be exerted by the plunger head this can'be quickly relieved by momentarily opening the needle valve H and turning the hand wheel 55 in the opposite direction. Should the operator be careless in permitting the piston 2| to be adjusted too high, nevertheless no damage to any part of the press will result since the safety relief valve 62 will prevent such excessive pressure being developed under any condition beyond the predetermined maximum permitted by the relief valve and its adjustable spring 63.

As will be apparent from the foregoing descriptionand explanation, very fine and accurate adjustments are easily possible through the medium of the piston-adjusting cap or hand Wheel 55 and thus my invention facilitates the obtaining of most efilcient results without excessive trial runs or loss of time, with a minimum of eifort and with the dangerous effects of carelessness to a considerable extent reduced.

In order to enable the cap 50 to be raised or lowered to a predetermined position, and there with cause. the maximum height of the plunger head to be at a precise predetermined point, I. provide a positioning gage for the cap 56, which positioning gage is shown in Figs. 10 and I1. This gage comprises an indicator arm 30, pivotally mounted at 9! on the lower front plate 89' of the housing so as to swing in a vertical plane. The bottom end of the arm til has an off-set; downwardly-extending finger 92 which bears against the top face of the cap 59. A spring 93, set in a recess in the front plate 89, has its upper endsecured at 94 and its lower end bears against a pin 95 on the underside of the arm 98 and is so arranged as to exert a constant tendency to swing the arm at in counter-clockwise direction (as viewed in Fig. 10). This action of the spring 93 thus holds the finger 92 constantly against the top surface of the cap 5c, and movement up or down of the cap (and consequently movement of the hydraulic piston controlled by the cap 59), will cause the arm to move; An indicator scale mounted on the plate 89 adjacent the top end of the arm 90, enables an exact reading ofv the position of the arm 96 to be made. Thus, with the aid of the scale 56 and the arm 98, the cap '59 (and therewith the plunger head) can be set for any exact predetermined position by'manipulation of the hand wheel 55.

This provision for making an accurate predetermined adjustment in my press quickly and easily is another important feature of my invention. For example, it would be possible by using a similar make-ready press, to determine the exact desired maximum pressing position for the plunger for printing. or embossing with a particular die or plate and for a particular grade of paper. This could all be determined on the make-ready press while the main operating press is in use, and then all that is required to set the main press is to adjust the same to the desired position determined on the make-ready press.

In the. press which I have illustrated and described the die is. shown mounted above the plunger. This I consider the preferred arrangement since all the pressure-producing mechanism can be located in the lower part of the housing or below the'head, thus making the entire machine more compact. However, it would be possible to have the positions reversed, thus having the plunger in the head with the toggle elements above the plunger and the hydraulic piston and cylinder above the toggle elements. This would correspond to the arrangement generally followed in intaglio presses with the plate below the pressing elements in the head above.

My invention could be employed with this arrangement as well as with the arrangement described and illustrated, and it is not my intention to limit my invention otherwise than as set forth in the claims.

I claim:

1. In a press of the character described, an element for producing a desired impression, a plunger located below said element and slidable up and down, upper and lower toggle members, said plunger normally connected with said upper toggle member, said upper and lower toggle members hingedly connected together, means for moving said toggle members alternately towards and away from alinement with each other, a hydraulic cylinder, a hydraulic piston within said cylinder and extending upward from cylinder, means connecting the bottom end of said lower toggle member and the upper end of said piston, a cap on the outside of said cylinder, said piston passing through said cap, limit meansassociated with said piston and cap to limit the upward movement of said piston with respect to said cap, means for raising or lowering said, cap, an inlet valve for hydraulic fluid in the lower portion of said cylinder, 2. source of hydraulic fluid connected with said inlet valve, a pressure gage connected with said cylinder, whereby the maximum upward travel of said plunger when actuated by said toggle members can be regulated by said cap, and whereby the pressure transmitted through said plunger can be limited to a predetermined maximum.

2. In a press of the character described, an element for producing a desired impression, a plunger located below said element and slidable up and down, upper and lower toggle members, said plunger normally resting on said upper toggle member, said upper and lower toggle members hingedly connected together, earn means for moving said toggle members alternately towards and away from alinernent with each other,

a hydraulic cylinder, a hydraulic piston within said cylinder and extending upward from said cylinder, means connecting the bottom end of said lower toggle member and the upper end of said piston, a screw cap on the outside of said cylinder, said piston passing through said cap, limit means associated with said piston and cap to limit the upward movement of said piston with respect to said cap, means for turning said cap whereby to raise or lower said cap, an indicator showing the position of said cap and therewith the position of said piston, an inlet valve for hydraulic fluid in the lower portion of said cylin der, a source of hydraulic fluid connected with said inlet valve, a pressure-control safety outlet valve in said cylinder limiting the hydraulic pressure within said cylinder, whereby the maximum upward travel of said plunger when actuated by said toggle members can be regulated by said cap, and whereby excessive pressure transmitted through said plunger can be prevented.

3. In a press of the character described, an element for producing a desired impression, a plunger located below said element and slidable up and down, upper and lower toggle members,

said plunger normally resting on said upper toggle member, a shaft carried by said upper and lower toggle members and attached to said members, a roller mounted on said shaft, a-ro tating cam, spring means holding said roller against said cam whereby to cause said toggle members to be moved alternately towards and away from alinement with each other, a base block, the bottom nd of said lower toggle member pivotally sup-ported on said base block, a hydraulic cylinder, a hydraulic piston within said cylinder and extending upward from said cylinder, said block mounted on the upper end of said piston, a screw cap on the outside of said cylinder, said piston passing through said cap, a shoulder on said piston engageable withsaid means for turning said cap whereby to raise or lower said cap, an inlet valve for hydraulic fluid in the lower portion of said cylinder, a source of hydraulic fluid connected with said inlet valve, a pressure-control safety outlet valve in said cylinder limiting the hydraulic pressure within said cylinder, means for adjusting said safety valve, whereby the maximum upward travel of said plunger when actuated by said toggle members can be regulated by said cap, and whereby excessive pressure transmitted through said plunger can be limited to a predetermined adjustable maximum.

4.. In a press of the character described, an element for producing a desired impression, a plunger located below said element and slidable up and down, upper and lower toggle members, said plunger normally resting on said upper toggle member, a shaft carried by said upperand lower toggle members and attached to said mem bers, a roller mounted on said shaft, a rotating cam, means holding said roller against said cam whereby to cause said toggle members to be moved alternately towards and away from alinement with each other, a base block, the bottom end of said lower toggle member pivotally sup-ported on said base block, a hydraulic cylina hydraulic piston within said cylinder and extending upward from said cylinder. said block mounted on the upper end of piston, a so 'ew cap on the outside of said cylinder, said piston passing through said can, a shoulder on said piston engageable with said cap, means for turnsaid Mp whereby to raise or lower said cap, me. for indicating the position of said cap and therewith the position of said piston, an inlet valve for hydraulic fluid in the lower portion of said cylinder, a source of hydraulic fluid. connected with said inlet valve, a pressuracontrol safety outlet valve in said cylinder limiting the hydraulic pressure within said cylinder, means for adjusting-said safety valve, a pressure gage connected with said cylinder, whereby the maximum upward travel of said plunger when actuated by said toggle members can be regulated by said cap. and whereby pressure transmitted through plunger can be limited to a pre determined adjustable maximum.

5. in an intaglio printing and embossing press of the character described, a hydraulic cyni r, a piston movable up and down cylinder and extending above the top oi said lder, a to 'e asseznbly mounted on the top id ni. :ona plunger supported by said toggle assembly, an element for producing a desired impression supported on said plunger, means for moving the toggle members in said to gle s alternately towards and away from nnment with each other, means for delivering hydrauli "a piston movable up and down in said cylinder and extending above the top of said cylinder, a toggle assembly mounted on the top of said piston, a plunger supported by said toggle assembly, an element for producinga desired impres- "sion supported onsaid plunger, means for moving the toggle members in said toggle assembly alternately towards and away from alignment with each other, means for delivering hydraulic ffiuidinto said cylinder below said piston, adjust- "able limit means connected to said cylinder and engageable by said pistonfor limiting the upwardmovement of .saidpiston so as to enable said piston to .be hydraulically maintained .in a predetermined supporting position, means for ad- 'justing said .limit means, and an indicator connected with .said limit means.

7. In an intaglio printing and embossing press of the character described, a hydraulic cylinder, 2. piston movable up and down in said cylinder and extending above the top .of said cylinder, a toggle assembly mounted on the top .of said piston, a plunger supported by said toggleassembly, an element for producing a desired impression supported on said plunger, means for moving the toggle members in said toggle assembly alternately towards and away from alignment with each other,1a coil spring .in said cylinderiheld under "compression between the cylin 'der'bottom'and the bottom of said piston .to urge "said piston upwardlyya hydraulic fluid reservoir,

J12 a channel leading from said reservoir to the bottom of said cylinder, a one-way valvein said channel causing hydraulic, fiuidto be drawn into said cylinder by the upward :movement of said piston, a pressure-control safety valve outlet leading from said cylinder to said reservoir to permit hydraulic fluid to pass from said cylinder back to said reservoir'when the pressure in said cylinder exceeds a predetermined amount, means for adjusting said safety valve outlet, and adjustable limit means connected to said cylinder and engageable by saidpiston ffor limiting the upward movement of said piston so as to enable said piston to be hydraulically maintained in a predetermined supporting position.

HOLMES B. GABBERT.

REFERENCES CITED The'following references are ofrecord in the file of this patent:

UNITED STATES PATENTS 

